<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<title></title>
	<style type="text/css">
		.nav{
			border: 0px solid blue;
			padding-left: 0;
			width: 1000px;
			margin: 200px auto;
			background:black;
		}
		.a1{
			list-style: none;
			color:white;
			/*border: 1px solid red;*/
			display: inline-block;
			width: 120px;
			height: 50px;
			line-height: 50px;
			text-align: center;
			margin: auto;
		}
		#b1{
			position: relative;
			margin: auto;
		}
		#b2{
			position: relative;
		}
		.subnav{
			position: absolute;
			list-style: none;
			margin-left:auto;
			border:1px solid yellow;
			display: none;
			color: orange;
			margin: left;
			width: 100px;
			text-align: center;
			padding: 1px;
		}
		#b1:hover .subnav{
			display: block;
			background: grey;
			background-color: skyblue;
		}
		#b2:hover .subnav{
			display: block;
			background: grey;
			background-color: skyblue;
		}
		.li:hover {
			color: blue;
		}
		.c1{
			width: 120px;
			height: 50px;
			border: 1px solid red;


		}
	</style>
</head>
<body>
	<ul class="nav">
		<li class="a1"  id="b1">网站首页
			<ul class="subnav">
				<li>目录1</li>
				<li>目录2</li>
				<li>目录3</li>
				<li>目录4</li>
				<li>目录5</li>
			</ul>
		</li>
		<li class="a1" id="b2">关于我们
           <ul class="subnav">
           	<li>目录1</li>
           	<li>目录2</li>
           	<li>目录3</li>
           	<li>目录4</li>
           	<li>目录5</li>
           </ul>
		</li>
		<li class="a1">资质认定</li>
		<li class="a1">政府扶持</li>
		<li class="a1">知识产权</li>
		<li class="a1">上市服务</li>
		<li class="a1">人才招聘</li>
		<li class="a1">联系我们</li>

	</ul>
</body>
</html>